I have had an EchoLink system up and running for a couple of years using Mastr Exec and MVP radios with 85.4 CTCSS access. I use a stock 85.4 decoder in the 440 repeater and have a 440 MVP with stock 85.4 encode/decode as the link radio. I have a Mastr Exec 2 meter remote base on a simplex frequency for the main interface (also with a stock decoder). A user transmits a 85.4 tone which is decoded in the 2 meter Exec and passed through a NHRC-4 controller to the 440 Exec transmitter (along with the audio) and is received by the MVP to put it on EchoLink. A user may use the 440 repeater to get on EchoLink also, as the tone is required to key up the repeater and is passed through to the MVP for EchoLink access.
I have had no problem with users being able to access either the repeater/remote base or get all the way to EchoLink. I did have another system with an encoder/decoder that allowed the user PL to get through to the link radio and the tone decode at the link would drop out on a regular basis during a transmission. I speculated that the reason was the user tone beating with the repeater transmit tone and going in and out of phase thus defeating the tone decode at the link site. That problem cleared up when the repeater was modified to get rid of the user tone before the transmit tone was added. 73 - Jim W5ZIT -----Original Message----- From: [EMAIL PROTECTED] To: [email protected] Sent: Fri, 5 Jan 2007 5:06 PM Subject: Re: [Repeater-Builder] Need: 131.8 Versatone for GE EXEC Board 190430740G, also information At 1/4/2007 05:57 AM, you wrote: >n9lv wrote: > > I am in need of at least five 131.8 versatone boards for the following > > GE tone board. Also, I need to know, are these board just encode, and > > is there a way to make them decode. I put one in one of the radios, > > it does send pl out the transmitter, however I do not get any audio > > from the speaker out of the receiver. > > > > Problem I am having is that the GE converted radios will not allow the > > PL tones to pass through them. I can take the repeater out of PL and > > the radios work just fine, and the audio is just fine. > > > > Any sugesstions? Thanks > > > > Mathew > >I think you are you using these radios for voting remote receivers? If >that's the case, are you sure you want to introduce yet another PL >response time into the equation? If not, consider FM'ing the >transmitters, and installing some sort of audio processor designed to do >the job of clipping and HPF'ing that fits the situation. While FMing definitely improves the low-frequency modulation performance of PM exciters, I've experienced good performance with my stock MVP PM exciters. I know from Dave Karr's experiments (or was it Virgil at S-Com, can't quite remember who did the tests a while back) that the harmonic distortion at low modulating frequencies and high deviation levels is a bit high. However, CTCSS deviation levels are quite low in practice (should never be more than 1 kHz). If the output from the RX discriminator is de-emphasized so as to "match" the pre-emphasis curve of the phase modulator, a very flat audio response that includes the CTCSS frequency range can be obtained. Basically this means lowering the "break point" of the de-emphasis network from the usual 300 Hz to just below the low end of the CTCSS range (40 Hz or so). > The AP-50 is one such animal. Most commercial equipment audio chain in > good from only 300 to 3000 cycles; it won't pass PL and it won't pass the > high-end audio that the voter relies on to properly vote. The phase > modulators that most of this equipment utilizes won't properly follow > audio that is recovered from the discriminator, and is why I choose to > install a real FM modulator in the radio set. A better sounding, better > working radio >will result; one that is transparent to the system. I have never tried >to FM a EXEC II; we've always used MASTR II's for remote satellite >receiver - link-back transmitter combo's, but, I don't see why it can't >be done. IMO the AP-50 is an excellent "final output" processor that enables a near-perfect balance between keeping the output clean and preserving repeat audio fidelity. However, for a remote receiver link I think you'd want to make it a 1:1 link with no limiting or filtering whatsoever. For that you could simply FM your TX, or use the CG HI (direct to the PM modulator) & apply the de-emphasis as described above. I've done this for my system which has a total of 3 links in the repeat path & have been told by some local FM "purists" that it sounds quite respectable. My ears do detect a bit of subtle low-pass filtering taking place somewhere; I believe it's due to the combined low-pass roll-off of each RX in the system as a result of the IF filtering but I could be wrong. Bob NO6B ________________________________________________________________________ Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection.
